1. Field of the Invention
This invention relates generally to multi-paned window systems and to the manufacture of such systems. More specifically, the present invention is directed to an improved window system having an innovative seal wherein the seal can be compressed only to a substantially uniform and substantially predefined thickness and wherein the seal provides exceptional insulation, weather resistance and adhesion characteristics.
2. Discussion of the Prior Art
Multi-paned window systems are known generally in the art, and such systems have two or more window panes encased in a window frame by means of a seal, typically a mastic-type product. Conventional mastics are generally thick, semi-liquid polymer sealants which are typically dispensed by means of a caulking gun or similar-type device; alternatively such sealants can sometimes be thickened and incorporated into a preformed tape and applied by hand.
The mastic will bond the sheets of glass together along their peripheral edges in a spaced apart relationship to thereby provide an air space between the glass plates. The sealed air space provides the window system with superior insulating qualities relative to conventional single-paned systems.
However, the flowable nature of many mastics during the manufacturing process often presents handling problems and can also result in undesirable migration of the polymer material. It may be difficult to obtain a uniform thickness of the mastic due to the mastic's semi-liquid nature. Although uniform thickness may initially be achieved, the glass panes may nevertheless shift and the mastic compressed or otherwise moved in a non-uniform manner. Such unwanted shifting and non-uniform mastic compression can be particularly pronounced if the window systems are stacked one on top of the other during the manufacturing process. Such stacking however is commonplace due primarily to space limitations and labor cost considerations.
If the window systems are stacked during manufacture, not only will each window tend to have a non-uniform seal around its periphery due to non-uniform stacking compression, but also the window systems at the bottom of the pile will tend to deform and be compressed more than windows located at the top. As a result, the gap between the glass panes of each window system will generally be non-uniform and somewhat unpredictable.
Similar-type extreme and/or non-uniform compression forces can occur in window systems having a crank mechanism used to pivot the window open or closed. Such cranking systems often place significant strain on the window system and typically cause substantial compression upon the window sealant.
Extreme and/or non-uniform compression forces can also occur if the multi-paned window system is used in an automobile or similar-type vehicle. Such forces can also occur if the sash is of a low cost, high compression design, such as where the sash framework must be partially pried open and pounded onto the periphery of the multi-paned window system to provide a tight friction fit without the need for a substantial amount of glazing or the like.
Non-uniform mastic compression can detract from the appearance of the window and can adversely effect the mastic's ability to bond, seal, and be weather resistant. If compression forces overly compress the mastic, such compression will reduce the mastic's ability to elongate or tolerate movement. Furthermore, a particularly soft or flowable mastic may be substantially squeezed out of the window system, substantially diminishing or destroying the intended seal.